This invention relates to fuel for internal combustion engines, and more particularly relates to means for separating contaminants from diesel fuel and the like, before the diesel fuel is delivered to the fuel filter from the fuel tank.
As is well known by those skilled in the art, the efficient operation of a conventional diesel engine and the like is contingent upon the presence of "clean" fuel, i.e., fuel free from contaminants and the like. As is appreciated by those conversant in the art, diesel fuel and the like tend to become contaminated with liquids such as water, and with particulate solids such as sand, rust, fungus, dirt, etc. Such contaminants are typically introduced into internal combustion engines while fuel is being replenished in a fuel tank, from rust or corrosion by-products being formed while the fuel is stored in the fuel tank, through leaks in the fuel system or related systems, etc.
Particulate solids are, of course, suspended in diesel fuel stored in a fuel tank and are subjected to the remedial action of fuel filters, prior to being delivered to the diesel engine. Depending upon the design of a fuel filter, and, whether such filter is sufficiently clean to be effective, at least some of these contaminants and impurities will be separated from the fuel before reaching the engine. But even the presence of minor amounts of water in diesel fuel cause maintenance problems which are exacerbated during cold weather. Obviously, while frequent maintenance checks of fuel filters and the like promote efficient operation of diesel engines and the like, such planned maintenance cannot assure that filters will be timely replaced to not only maximize fuel utilization, but also minimize pollution to the environment.
There have been several developments in the art to promote the efficient operation of the internal combustion engine by minimizing the intrusion of contaminants and impurities into the engine concomitantly with the fuel. These developments have generally sought to purify the fuel before being delivered to diesel engines and the like, by separating the contaminants and impurities from the fuel prior to the fuel being received by the internal combustion engine via conventional oil filters. For example, in U.S. Pat. No. 3,362,534, Kay discloses a fuel-water separation apparatus in which water entrained in fuel is separated therefrom by mechanical action. More particularly, the Kay apparatus causes the water-fuel mixture to flow along an inclined, roughened and scabrous surface wherein water droplets coalesce to form globules which gravitate to the bottom thereof. According to Kay, prerequisite to separation of entrained water from fuel is the laminar flow of the contaminated fuel along the roughened surface to avoid sustaining the entrained condition, on the one hand, and to avoid re-entraining the water globules, on the other hand. The Kay apparatus is constructed with a baffle shaped like a segment of a cylinder which is designed to achieve laminar flow in a cylindrical tank.
As another example, Shepherd, in U.S. Pat. No. 4,789,098, teaches an apparatus which improves upon the hereinbefore described Kay fuel-water separation technique by including a heated baffle plate with a degree of roughness selected to provide enhanced moisture separation efficiency. Constructed with parabolically shaped depressions, the Shepherd baffle plate promotes surface contact with the laminar-flowing fluid.
Contrary to the teachings of Kay and Shepherd, Uzeta teaches in U.S. Pat. No. 4,986,907 a fuel purifying apparatus which effects separation of water and other contaminant from fuel by the action of turbulent fluid flow instead of laminar flow. The Uzeta apparatus comprises a fuel discharging orifice adjacent a heated metal deflector plate which extends diametrically and longitudinally in an elongated shell. Fluid discharged onto the angularly positioned deflector plate flows in a circular motion, causing turbulent flow thereof. Impurities and the like which are heavier than diesel fuel gravitate to the bottom of the shell, for discharge.
Notwithstanding these and related developments in the art, there appears to be no apparatus which provides sufficient centrifugal fluid flow to enable effective separation of contaminants and impurities from diesel fuel and the like, and simultaneously prevent re-mixing of the separated components with the virgin fuel. Thus, it would be advantageous to utilize an apparatus which generates sufficient turbulent, circular fluid flow to promote the gravity-separation of impurities and the like from fuel, but which inherently controls and isolates the respective flow of the fuel and the gravitating or already gravitated impurities, to prevent inadvertent re-mixing thereof. Accordingly, these limitations and disadvantages of the prior art are overcome with the present invention, and improved means and techniques are provided which are useful for effectively and permanently separating impurities and contaminants from diesel fuel and the like, prior to the fuel reaching conventional fuel filter and then the internal combustion engine.